Blood Pressure Regulation Flashcards
1
Q
What is cardiac output?
A
heart rate x stroke volume
2
Q
Define ESV and EDV
A
- ESV; end-systolic volume. Volume of ventricle post contraction
- EDV; end-diastolic volume. Volume of ventricle just before contraction
3
Q
Elements of blood pressure
A
- Total Peripheral Resistance (TPR)
- Cardiac output (CO)
- P= CO x TPV
4
Q
How is cardiac output controlled?
A
- by the sympathetic and parasympathetic nerves that affect…
- heart rate
- force of heart contraction
5
Q
How is TPR controlled?
A
by nervous and chemical signals that affect the constriction and dilation of arterioles and venules
6
Q
Measuring Blood Pressure
A
- arterial blood pressure; measured in mmHg
- Systolic BP; maximal arterial BP during heart contraction
- Diastolic BP; minimum arterial BP during heart relaxation
- Can take mean arterial pressure
7
Q
Average Blood pressure in domestic mammals
A
SBP; 125-145
DBP; 80-95
8
Q
Short term regulation of blood pressure
A
- Baroreceptors; in arterial walls
- increase AP firing rate in response to increased stretch
- most important baroreceptors are in the carotid artery and the aortic arch
- carotid sinus baroreceptors; detect changes in pressure to the brain
- aortic branch baroreceptors; detect changes in pressure to the body
9
Q
Long term regulation of blood pressure
A
Renin, angiotensin and aldosterone system
- if BP decreases for over a minute, kidney gets involved
- rechanneling of blood to vital organs
- activation of RAAs occurs
10
Q
The RAAs system
A
- decrease of perfusion detected by JGA in macula densa in glomerular capillary
- renin is released by JG cells; cleaves angiotensinogen to form angiotensin I
- angiotensin I converted to angiotensin II by ACE in the lungs
- angiotensin II is a vasoactive product; causes vasoconstriction, stimulates release of aldosterone from adrenal gland and ADH from pit. gland
- BP increases
11
Q
Aldosterone function
A
causes nephron distal tubules to reabsorb more Na+ and water which increased blood volume
